Wingnut
Member
Hello all, I'm new to the trawler scene and really enjoy reading this forum!! I have a trawler with a davit with no tags or id. I need some help determining its weight capacity. Any help is greatly appreciated!
Davit identification
- Thread starter Wingnut
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If you have answers, please help by responding to the unanswered posts.
If you have answers, please help by responding to the unanswered posts.
That is what is called a pipe davit. Davits can be made by any aluminum or stainless steel tubing fabrication shop, so there might be hundreds of suppliers.
One large supplier of these is Nick Jackson, see Pipe Davits. But his current ones at least have a small truss that strengthens the davit but your pics don't have that. Also your pics show reducing sections as you near the end.
Why do you need to know? To get a rough idea of the lift rating, compare the diameter of your outer pipe with the diameter of Jackson's davit without the truss. The physics of the loads on that outer section should be approximately the same so they need to be the same diameter for similar weight capacity.
For example, Jackson's pipe looks to be 2-7/8" OD for 300 or 500 lb davits. Compare that with yours.
If you want to buy a winch, then Nick Jackson probably could help, no matter who built it.
David
One large supplier of these is Nick Jackson, see Pipe Davits. But his current ones at least have a small truss that strengthens the davit but your pics don't have that. Also your pics show reducing sections as you near the end.
Why do you need to know? To get a rough idea of the lift rating, compare the diameter of your outer pipe with the diameter of Jackson's davit without the truss. The physics of the loads on that outer section should be approximately the same so they need to be the same diameter for similar weight capacity.
For example, Jackson's pipe looks to be 2-7/8" OD for 300 or 500 lb davits. Compare that with yours.
If you want to buy a winch, then Nick Jackson probably could help, no matter who built it.
David
Woodland Hills
Guru
You will also need the wall thickness of the pipe to compare apples to apples. When I upgraded mine from an 8’ boom to a 10’ the stanchion increased in OD as well as decreasing in ID. In other words it got a lot thicker.
Pete Meisinger
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That lifting davit looks to be home made. Not that it's a bad thing but there is no way to determine its capacity. Judging by the fact that there is no bearing for rotation I'm thinking probably less than 500 lbs.
Turn it towards the dock or deck and rig up a board to sit on. Try your weight and judge twist and strain. Then add a couple kids or weights or the Admiral (might be fun). Keep close to the ground so you don't have far to fall. Have someone checking the mounting plate, if it starts to show strain or flex better abandon the test.
pete
Turn it towards the dock or deck and rig up a board to sit on. Try your weight and judge twist and strain. Then add a couple kids or weights or the Admiral (might be fun). Keep close to the ground so you don't have far to fall. Have someone checking the mounting plate, if it starts to show strain or flex better abandon the test.
pete
Comodave
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Welcome aboard. I agree that it looks homemade. Without any truss to add support, I would suspect that it will be in the 3 to 400 pound range.
C lectric
Guru
Most lifts like that also go through the upper deck and land on the back deck for support. If yours does not have that lower deck support then that will substantially reduce capacity.
Does the vertical pipe go through the upper deck and land on the lower deck?
Does the vertical pipe go through the upper deck and land on the lower deck?
Wingnut
Member
Yes it goes through and mounts to the lower deck
GregBrannon
Guru
Welcome! Tell about your boat and post pictures when you can.
Greg.
Greg.
Pete Meisinger
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When I look more closely at the pictures it confirms to me that it is home made.But based on your description that the post goes all the way through the deck and the fact that closer examination of the picture shows a star shaped gusset or reinforcer on the top of the davit for extra strength at the bend. I revise my original estimate of 500 lbs. I think it will hold quite a bit more.
Ill stick with my original idea to test it though.
pete
Ill stick with my original idea to test it though.
pete
